Strictly on the basis of the comparison of exemplars with questioned documents, the identification of modern electronic typewriters is rare. Of course, the analysis of a carbon film ribbon to associate a particular electromechanical or electronic machine with a particular questioned document is well established. However, little has been written concerning the identification of an electronic typewriter based solely on the examination of its work. Estabrooks (1983) illustrated extreme wear defects in high-use printwheels. Unfortunately, this extreme form of defect is rarely encountered in actual casework. Hilton's (1986) conclusion concerning the use of traditional methods for the identification of documents generated by printwheel typewriters is not convincing. Therefore, any true typeface defect encountered in the work of an electronic machine should be given considerable weight in formulating an opinion as to source determination.

The examination of several cases, over the past several years, involving documents suspected of having been prepared on electronic printwheel typewriters exhibited what appeared to be extensive damage to the typeface, the cause of which was initially unknown. This paper will describe and illustrate the cause of damage in this type and its value in casework. It was subsequently discovered that individuals were unintentionally reversing the printwheel in typewriters, usually lower-end models, and then attempting to operate the machine. Because I had conducted prior research concerning electronic typewriter hammer-mark impressions on documents, the cause of the defect patterns became apparent (Anthony 1988) .

Experimentation has shown that it is possible to reverse a noncartridge-type printwheel and still operate the machine, although improperly, thus potentially causing severe damage to characters. Discovery of similar defect patterns would confirm that the questioned document was prepared on an electronic printwheel typewriter and permit positive statements concerning the source of questioned documents.

Figure 1 exhibits vertical voids in all letters in the photograph. Note that the "w" and "s" in this figure show repeated damage to the typeface, the result of the machine being operated, in all likelihood, in the bold mode.

Figure 2 depicts damage to the printwheel's capital letter "I," on the left, and the resulting printed image on the right, the cause of which is certainly from an electronic typewriter's hammer.

Multiple vertical defects to characters, the result of repeated strikes to the typeface by the typewriter's hammer.

In Figure 3, damage to the letters in the word " to," in red, has been superimposed with a standard hammer impression, in green, from a Royal electronic typewriter. This was accomplished on a Projectina Universal Comparison Projector. Other hammer impressions from files can be superimposed over the voids with similar results. There can be little doubt, based on examinations of these illustrations, as to the cause of this type of damage to printwheel characters.

Encountering hammer impression defects in cases concerning typescript will probably be the exception rather than the norm. But any explanation as to the cause of individual defects to typeface is most valuable in the identification process of associating an electronic typewriter to its work.

With computers becoming so prevalent in business and home life, the document examiner is likely to encounter evidence generated by computer printers now more than ever. This situation is exemplified by a recent case where disputed documents were created on a printer that uses a new process.

In February 1998, the Colorado Bureau of Investigation Crime Laboratory received evidence from an investigation of the sale of suspicious Super Bowl XXXII tickets. The Denver Broncos were playing in the game, and every devoted fan sought to procure tickets. This huge demand provided scheming entrepreneurs a means to offer such opportunities, for a price. Prior to game day, a local investigator entered into an agreement with a suspect to purchase two tickets for $1,600 cash. Following the transaction, the suspect was apprehended, and the tickets were seized. The investigator suspected that the tickets were forged and submitted the evidence to the crime laboratory for examination and comparison.

The questioned and authentic Super Bowl tickets were examined visually, microscopically, and spectrally. The examinations concluded that the characteristics of the questioned and authentic tickets were inconsistent, and the questioned tickets bore features consistent with the Micro Dry printing technology used in the MD-Series of printers patented and manufactured by Alps Electric, Inc. (San Jose, California). Microscopic examinations revealed significant characteristics differentiating the Micro Dry process from other printer technologies such as ink jet and laser. In the Micro Dry process, the color image appears to be sitting on the paper surface as a series of dots in a cross-hatched pattern. This contrasts with the ink absorption, bleeding, and splattering which is characteristic of the ink jet process and the toner piles associated with the xerographic process used in laser printers. It is interesting to note that metallic silver and blue were used in association with cyan, magenta, yellow, and black to create the color image.

An explanation of the Micro Dry process aids in understanding how the image is created. The dry ink process uses pigmented ink, which is applied to any suitable substrate via a mylar ribbon. A thermal printhead melts the ink, which is then transferred to the paper where it cools down and hardens permanently on the surface (Reis 1997). The printer is designed to lay down colors one at a time in four passes. This means that the printer has four ribbon slots, which enable it to print in a multitude of color combinations. The ribbon cartridges are available in many colors including traditional cyan, magenta, yellow, and black; metallic cyan, magenta, gold, and silver; multicolor; white; and photo cyan, magenta, and yellow (Alps Online 1997).

The use of this new technology to counterfeit the Super Bowl XXXII tickets discussed in this case exemplifies how document examiners must stay current with the introduction of new office products. This information on the Alps Micro Dry process may assist the examiner in differentiating this new addition from the myriad of other printers available today.